Al the pictures of Elliptical galaxies that i've seen fade out into the surrounding space and don't have that edge.
In computer simulation, everything must have a border. Elliptical galaxy model is not an exception.
Some do go to a bright point in the centre (e.g:), but often the central bright part is larger too - it doesn't just increase to a point with a gradient. e.g. IC 1101:
This is because how original hi-dynamic range photograph was converted to lo-dynamic range jpeg image. Telescopes takes photos using 16- to 24-bit depth CCD matrices, and astronomers uses all available data to make measurements. For public release, photos must be converted to 8-bit depth jpeg/bmp/png/whatever images to be able to display them on monitors. Some exposure conversion is used for this. Any photographer who is familiar with HDR photo knows this.
Though granted I don't know how much of that is due to photo exposure. But they do just look 'artificial' to me in 0.9.8.0 at least - too mathematically defined.
Of course it is, because SE uses mathematically defined analytical model! It is called De Vaucouleurs profile and widely used by astronomers:
http://www.astro.rug.nl/~ahelmi/galaxies_course/class_VII-E/ellip-06.pdf
Center of the galaxy is indeed very point-like, because its surface brightness is thousands times larger than the brightness of a middle parts of the galaxy. While observing galaxies through telescope with an eye, you usually see only the central parts of the core, which looks like a fuzzy star.
And also they never have any dust in them, which sometimes does happen (e.g. NGC 1316):
It is impossible to define in a pure analytical model. Such complex galaxies must be rendered in other way, which SE supports for spiral galaxies:
As another option, could Ellipticals not be rendered the same way as the central bulges of spiral galaxies? Or even just with their own models and textures like spiral galaxies?
A custom sprite model for E galaxies can be created in the same way as for spiral galaxies, there is a
tutorial. But 99% of E galaxies have only bulge, so De Vaucouleurs model is enough for them; it also takes no memory and has 100 times faster rendering. Some of the first versions of SE had all E galaxies implemented using sprite models, but the result was not very good. The analytical De Vaucouleurs model is much more realistic.